Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.util.*;
import java.io.*;

public class Main {
	public static int[][] ara1,ara;
	public static void main(String[] args) throws Exception {
		InputReader in = new InputReader(System.in);
		
		int n = in.nextInt();
		int m = in.nextInt();
		
		ara1 = new int[n+1][m+1];
		
		for(int i=1;i<=n;i++) {
			for(int j=1;j<=m;j++) {
				ara1[i][j] = in.nextInt();
			}
		}
		
		boolean flag2 = false;
		if(m<n) {
			flag2 = true;
			ara = new int[m+1][n+1];
			for(int i=1;i<=n;i++) {
				for(int j=1;j<=m;j++) {
					ara[j][i] = ara1[i][j];
				}
			}
			m = m^n^(n=m);
		} else {
			ara = new int[n+1][m+1];
			for(int i=1;i<=n;i++) {
				for(int j=1;j<=m;j++) {
					ara[i][j] = ara1[i][j];
				}
			}
		}
		
		int[] rs = new int[n*505+2];
		int[] cs = new int[m*505+2];
		int cnt = 0;
		
		for(int i=1;i<=n;i++) {
			int mn = Integer.MAX_VALUE;
			for(int j=1;j<=m;j++) {
				mn = Math.min(mn, ara[i][j]);
			}
			
			if(mn>0) {
				for(int j=1;j<=mn;j++) {
					rs[cnt++] = i;
				}
				
				for(int j=1;j<=m;j++) {
					ara[i][j] -= mn;
				}
			}
		}
		
		int cnt2 = 0;
		for(int i=1;i<=m;i++) {
			int mn2 = Integer.MAX_VALUE;
			for(int j=1;j<=n;j++) {
				mn2 = Math.min(mn2, ara[j][i]);
			}
			
			if(mn2>0) {
				for(int j=1;j<=mn2;j++) {
					cs[cnt2++] = i;
				}
				
				for(int j=1;j<=n;j++) {
					ara[j][i] -= mn2;
				}
			}
		}
		
		boolean flag = false;
		for(int i=1;i<=n;i++) {
			for(int j=1;j<=m;j++) {
				if(ara[i][j]!=0) {
					flag = true;
				}
			}
		}
		
		if(flag) {
			System.out.println(-1);
		} else {
			System.out.println(cnt+cnt2);
			for(int i=0;i<cnt;i++) {
				if(flag2) {
					System.out.println("col " + rs[i]);
				} else {
					System.out.println("row " + rs[i]);
				}
			}
			for(int i=0;i<cnt2;i++) {
				if(flag2) {
					System.out.println("row " + cs[i]);
				} else {
					System.out.println("col " + cs[i]);
				}
			}
		}
	}
	
	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;
		
		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream));
			tokenizer = null;
		}
		
		public String next() throws Exception {
			while(tokenizer==null || !tokenizer.hasMoreTokens()) {
				tokenizer = new StringTokenizer(reader.readLine());
			}
			return tokenizer.nextToken();
		}
		
		public String nextLine() throws Exception {
			return reader.readLine();
		}
		
		public int nextInt() throws Exception {
			return Integer.parseInt(next());
		}
		
		public long nextLong() throws Exception {
			return Long.parseLong(next());
		}
		
		public double nextDouble() throws Exception {
			return Double.parseDouble(next());
		}
	}
}